GANIL, Caen
Solid state rf amplifiers are being considered for an increasing number of accelerator applications, both circular and linear. Their capabilities extend from a few kW to several hundred kW, and from less than 100 MHz to above 1 GHz, for operation both in the linear and saturated regime. This talk will review the state of the art and future prospects of rf power amplifiers for accelerator applications.
HUST, Wuhan
Funding: Work supported by National Nature Science Foundation of China, 10435030
In order to reduce the cost of the signal generator comprising a high performance direct digital synthesizer (DDS), the method of picking up a desired aliased signal of DDS output is adopted in the study. The chip AD9850 is used to synthesize RF signal in the system, and the amplitude modulation of the system is achieved by altering the external connection resistance of the chip. The output frequency is tunable from 99.5 to 101MHz. The principle and the test results of the signal synthesizer will be presented. The amplifier based on tetrode technology can deliver the 10kW RF power in a continuous wave (CW) mode of operation. The driver amplifier consists of two solid-state modules, and it can provide the tetrode with up to 300W input power. The tetrode operates in the grounded cathode configuration. The conceptual design of the final stage amplifier will also be demonstrated in this paper.
CRE, Wuppertal
The modular architecture of high power solid state rf amplifiers for the frequency range of 72 to 3000MHz is described. The characteristic features of the modular components are presented, focusing on the multi transistor amplifier modules delivering a power in the 0.5 to 1.5 kW range, the transmission line combiner system combining up to 150 amplifier modules, the monitoring of the rf power flow in the system and other relevant performance parameters, as well as the heat exchanger concept and the digital amplifier control system.
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
EMMA (Electron Model for Many Applications) is a non-scaling Fixed Field Accelerating Gradient (NS-FFAG) accelerator presently in the process of being built at Daresbury Laboratory as a proof of principle demonstrator for proton/carbon therapy application. Its aim is to take an injected beam from ALICE (Accelerators and Lasers in Combined Experiments) at 10MeV and accelerate it to 20MeV, so that the characteristics of NS-FFAGs can be studied. The beam is to be accelerated by 19 identical 1.3GHz RF cavities, which each need to provide the same accelerating voltage to the beam. The initial design stage of the RF system design has been completed, utilising three commercial suppliers of the major RF sub-system components.
IPN, Orsay
Funding: EURISOL Project
The development of RF power couplers for superconducting low-beta SPOKE cavities, performed at Nuclear Physics Institute in Orsay in the framework of the EURISOL Design Study, has led to the design of a 20 kW RF power coaxial coupler showing very good RF performances and the implementation of a test stand to condition two of these couplers at 20 kW CW power in the traveling wave mode at 352,2 MHz by using a half-wave resonant cavity. Composed by a ceramic disk, the coaxial power coupler developed shows on one hand a very good 50 ohms matching on a large bandwidth like 760 MHz, after an electromagnetic optimisation of the window area, and on the other hand a simplified design with regard to the classic coaxial couplers. Characteristics of the power coupler and the test stand will be described, and the low RF power test of the coaxial window and the conditioning at high RF power of two couplers will be presented.